In all my experience with Jaguars I have never heard of a Raymond Mays head for same. Ford Zephyrs yes, but Jaguars no. It is nearly impossible to fit 3 carbs to a mark 2 without cutting the inner guard. The Wills race was for standard cars and the black Mk2 that Archibald raced had to be returned to stndard to compete there. I refitted the D cams and 2'' SUs for the new owner whilst at Galt Motors. The overdrives are borderline for the torque on a Jaquar motor in top let alone using it in a lower gear.